Perturbed-Angular-Correlation Study of the Electric-Field Gradient in 181Hf-doped and Implanted Indium Sesquioxide

M. RENTERÍA; F.G. REQUEJO; A.G. BIBILONI; A.F. PASQUEVICH; J. SHITU; K. FREITAG

PHYSICAL REVIEW B - CONDENSED MATTER AND MATERIALS PHYSICS

American Physical Society

Lugar: Ridge,NY; Año: 1997 vol. 55 p. 14200 - 14207

0163-1829

We studied the hyperfine interactions of 181TaTa181 in In2O3InIn2o33 by means of perturbed-angular-correlation (PAC) measurements. We prepared thin films of indium sesquioxide with different degrees of initial amorphism and implanted them with 181HfHf181. Chemically prepared indium-sesquioxide powder samples were also made starting from neutron-irradiated HfCl34, which provides the 181HfHf181 PAC probes. PAC experiments were performed on each sample at room temperature, after each step of annealing programs at increasing temperatures up to the full crystallization of the samples. The results indicate that the PAC probe occupies preferentially the axially symmetric cation site. Point-charge-model calculations were performed. The calculated asymmetry parameters η were compared with those obtained in 181HfHf181 PAC experiments performed also on other binary oxides, showing that the symmetry of the electric-field-gradient (EFG) tensor at 181TaTa181 cation sites in binary oxides is mainly determined by the nearest-neighbor oxygen-ion distribution around the probe. Comparisons of the experimental results in bixbyites obtained for both PAC probes, 111CdCd111 and 181TaTa181, show that the local EFG in bixbyites, are strongly dependent on the geometry of the sites and the electronic configuration of the probes.